Cytological screening and 15 years' follow-up (1986-2001) for early esophageal squamous cell carcinoma and precancerous lesions in a high-risk population in Anyang County, Henan Province, Northern China

Background: Anyang County and nearby Linzhou (formerly Linxian) in Henan, Northern China have been well recognized as the highest incidence area for esophageal squamous cell carcinoma (SCC) in the world. SCC remains the leading cause of cancer-related death in these areas and the natural history for esophageal precancerous lesions is not clear. Methods: In the present study, to determine the significance of cytological examination and natural history for SCC, esophageal balloon cytological screening and follow-up studies have been performed 2273 symptom-free subjects in Anyang County since 1986. Based on cellular morphological changes, esophageal epithelial cells were classified as normal (NOR), inflammation (IN), hyperplasia (HYP), dysplasia (grades I and II) (DYS I and DYS II), near squamous cell carcinoma (NSCC) and SCC. Results: The prevalence of NOR, IN, HYP, DYS I, DYS II, and NSCC was 22.7, 3.6, 33.6, 21.5, 10.7, and 3.8%, respectively, in males and 25.8, 5.7, 33, 18.9, 10.4, and 3.8%, respectively in females. No difference was observed between the male and female subjects (p > 0.05). Of the 2273 subjects examined, 2199 subjects entered the final follow-up analysis (97%). During the 15 years' follow-up on these subjects, 94 new cases (4.2%, 94/2199), including 91 with SCC (97%, 91/94, 58 males and 33 females) and 3 with GCA (3%, 3/94, one male and two females) were identified with a mean time of 8 ± 4.6 years after entry of the follow-up. The incidence for SCC in males was higher than that in females (p < 0.05). The rate for SCC development increased apparently from the groups of NOR (2.4%) to DYS I (5%), DYS II (8.3%), and NSCC (10.3%) (p < 0.001). The prevalence of DYS and NSCC increased significantly with age. Conclusions: The present results indicate that esophageal balloon cytology is a reliable approach for early SCC and precancerous lesions screening and that DYS and NSCC are important markers for high-risk subjects with predisposition to SCC. Close follow-up to the subjects with HYP, DYS and NSCC may shed light on the natural history for human esophageal carcinogenesis.